searchInRotatedSortedArray.js

/*
There is an integer array nums sorted in ascending order (with distinct values).
Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k.
Given the array nums after the possible rotation and an integer target, return the index of target
if it is in nums, or -1 if it is not in nums.

You must write an algorithm with O(log n) runtime complexity.

Example 1:
Input: nums = [4,5,6,7,0,1,2], target = 0
Output: 4

Example 2:
Input: nums = [4,5,6,7,0,1,2], target = 3
Output: -1

Example 3:
Input: nums = [1], target = 0
Output: -1

Constraints:
    1 <= nums.length <= 5000
    -10^4 <= nums[i] <= 10^4
    All values of nums are unique.
    nums is an ascending array that is possibly rotated.
    -10^4 <= target <= 10^4
*/

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
function search(nums, target) {
    let left = 0, right = nums.length - 1;

    while (left <= right) {
        const mid = Math.floor((left + right) / 2);
        if (nums[mid] === target) return mid;

        // Left half is sorted
        if (nums[left] <= nums[mid]) {
            if (target >= nums[left] && target < nums[mid]) right = mid - 1;
            else left = mid + 1;
        } else {
            // Right half is sorted
            if (target > nums[mid] && target <= nums[right]) left = mid + 1;
            else right = mid - 1;
        }
    }
    return -1;
}

// Example usage:
console.log(search([4, 5, 6, 7, 0, 1, 2], 0)); // Output: 4
console.log(search([4, 5, 6, 7, 0, 1, 2], 3)); // Output: -1